My thoughts after playing Demo v0.1:
Premise: It is certainly an original take on the incest genre!
What I dislike is that the abuse and drugging by the brothers has already happened at the start of the game. It portrays the brothers as assholes and the MC as the victim. While the brothers otherwise don't act like assholes and the MC is actually willing to explore a sexual relationship with them willingly. So it's unnecessary.
The dad is also being put in a difficult position: he can hardly approve what his sons are doing, but kicking them out of the house would kill the story. Not kicking them out of the house makes him look weak though.
Gameplay: The game presents you with a couple of choices, of which it's not at all clear what the impact will be later. For example the question what to put on your bread. The next question: to accept a glass of milk from your brother or not, is bugged. The milk was drugged but also if you refuse the milk, you still get drugged. Both are (in my opinion) bad form. I think choices should be clear where they lead (like accepting the milk) or there should be a walkthrough which makes the choices clear.
Please do NOT make this a sandbox! A VN is fine!
Language: No big complaints.
Renders: They are not fantastic (in particular, lighting and facial expressions can be better) but they are definitely servicable.
Verdict (if it were a real review, which it isn't because it's too early): 3 / 5. If the choices and renders can be improved, 4 / 5. For 5 5 / 5 I would like to see the drugging / rape being completely avoidable. But in any case I will keep following the game!